Abstract:

In this study, a method of high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) was established for determination of galactose, glucose, mannose and fructose from hydrolyzed tea polysaccharides. METROSEP CARB 1 (150×4.0 mm)anion exchange column was used as separation column. The 4 kinds of monosaccharides were eluted by 6.0 mmol/L NaOH at 1.0 ml/min of flow rate for 45 min. Under the optimized conditions, their detection limits are 0.125 mg/L to 2.0 mg/L (injection volume 20 μl, peak height taken as quantitative analysis index). The RSDs of peak height and retention time are 5.82% to 14.19% and 2.03% to 2.26%, respectively for 7 continuous determinations of mixed solution of 20 mg/L galactose, glucose, mannose and 30 mg/L fructose. The spike recovery rates of galactose, glucose, mannose and fructose from hydrolyzed polysaccharides of green tea, Pu＇er tea, oolong tea and black tea are 91.8% to 99.3%.

Key words: anion exchange, pulsed amperometric detection, tea polysaccharides, galactose, glucose, mannose, fructose